BATT program awards more than $8 million for innovative research projects on lithium battery anodes

(Nanowerk News) The Batteries for Advanced Transportation Technologies (BATT) Program has announced the funding of eight R&D projects on lithium battery anodes. BATT is funded by the Department of Energy's Office of Vehicle Technologies and is managed by the Lawrence Berkeley National Laboratory as part of its Carbon Cycle 2.0 initiative.

The FY 2010 BATT Request for Proposals on the "Synthesis and Characterization of Novel Anode Materials and Structures for Use in Lithium Batteries" has resulted in new projects that can help accelerate the application of such batteries in plug-in hybrid electric vehicles and electric vehicles. These projects focus on developing next-generation anodes to increase the energy and decrease the cost of lithium batteries while maintaining safety and cycle life.

The awardees include two national laboratories, five universities, and one private non-profit research institute and are listed below, along with a brief description of their projects. The total requested funds are $8.54 million over four years.

This project will design high surface-area metal foam architectures as substrates for metal or intermetallic anodes. These new architectures will be superior to conventional laminated electrodes due to the enhanced stability derived from direct chemical bonding of the active materials to the current collector. The goal is to design anodes that will deliver a reversible capacity of at least 500 mAh/g with a lifetime of at least 500 cycles.

This project will synthesize nano-sized metal-based anodes, with most emphasis being placed on nano-tin. Additionally, other electroactive species will be incorporated so that greater lithium insertion rates can be obtained for safe and faster charging. The goal is to develop anodes with volumetric energy densities that approach double those of current carbon anodes, while still maintaining at least 400 mAh/g.

Drexel University (Yury Gogotsi, Michel Barsoum): New Layered Nanolaminates for Use in Lithium Battery Anodes

This project will explore a new class of materials combining the laminate structure of graphite with silicon, tin and other elements that can provide a higher lithium uptake per atom and lead to an improved capacity. The goal is to offer combined advantages of graphite and silicon anodes with a higher capacity than graphite and less expansion, longer cycle life, and a lower cost than silicon nanoparticles.

This project will use atomic layer deposition to coat amorphous-silicon anodes with an artificial solid electrolyte interphase layer to help minimize degradation upon volume expansion of the silicon during charging. In addition, flexible organic coatings will be deposited via molecular layer deposition to accommodate this volume change. The goal is to produce an anode with unprecedented high capacity and high rate that is capable of thousands of cycles.

This project will synthesize anodes targeted to reach specific capacity of more than 1,500 mAh/g with minimal capacity fading in 500 cycles at 1C rates. The layered structure of graphene sheets and SiOx nanoparticles can accommodate volume change or phase transformation of the SiOx materials by providing good electric contact between highly conductive graphene layers during charge/discharge processes, leading to enhanced cycling stability. An elastic binder polymer with Li-ion conductivity will be used to further accommodate volume change.

This project aims to synthesize silicon clathrate anodes that are designed to exhibit a volume expansion of only 9%, compared with 300% for the lithiation of crystalline silicon. Because of the small volume changes during lithiation, silicon clathrate anodes have the potential for high specific energy density, while avoiding capacity fading and improving battery life.

This project will explore a hierarchical porous electrode concept to wire up silicon nanoparticles, which can be synthesized at low cost and in large scale. In addition, this project will investigate strategies to limit electrolyte penetration into the silicon nanoparticle anode and will modify the nanoparticle surface to obtain a stable solid electrolyte interphase layer for long-term cycling.

This project will use cost-effective methods to synthesize amorphous silicon and Li-Si alloys and carbon- and boron-based heterostructures. In addition, this project will explore thermoplastic resin binders with chemical, physical, and electrochemical attributes superior to the currently used poly-vinylidene fluoride for keeping silicon particles in contact and preventing electrode cracking during cycling. The project goals include reversible capacities exceeding 2000 mAh/g and high rate capability.

The BATT program received 88 white papers and encouraged 28 applicants to submit full proposals. A selection committee composed of leading lithium battery experts reviewed each proposal and recommended eight for funding.

BATT is the premier fundamental research program in the U.S. for developing high-performance, rechargeable batteries for electric and hybrid-electric vehicles.